@import url(http://some/path/to/css1.css);
@import url(http://some/path/to/css2.css) screen and (max-width: 1024px);
@import url(http://some/path/to/css3.css) supports(display: grid) screen and
  (max-width: 400px);
@import url(http://some/path/to/css4.css) supports(display: grid);
@import url(http://some/path/to/css5.css) layer;
@import url(http://some/path/to/css6.css) layer;
@import url(http://some/path/to/css7.css) layer(layer-name) supports(display: grid) screen and (max-width: 1024px);
@import url(http://some/path/to/css8.css) layer(layer-name) screen and
  (max-width: 1024px);
@import url(https://some/external/css);
body {
  background: red;
}

.b {
  background: red;
}

